Slide-holder for magic-lanterns



(No Model.)

W. S. BARSTOW.

SLIDE HOLDER POR MAGIC LANTERNS'.K

No. 300,558. Patented June 17, 1884.

N. Prima Phcla-umognpncr. wamingwn, llc.

Parel-vr "VILTJIAM S. BARSTOV, OF BROOKLYN, NEV YORK.

SLIDE-HOLDER FOR MAGICI-LNTERNS.

SPECIFICATION forming part of Letters Patent No. 300,558, dated .Tune 17, 1884.

' Application filed January 9, i834. (No model.)

irc @5E 10.71.0122, t may concern,.-

Be itknown that I, WILLIAM S. Blinsrow, of Brooklyn, in the county of Kings and State of New York, have invented a new and useful Improvement in Slide-Holders for Magic- Lanterns, Heliostats, etc.; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawing, and to the letters ofv reference marked thereon, making a part of this specification.

My invention relates to the slide-holder for a magic-lantern, stereopticon, or similar optical instrument.

It consists in uniting the parallel grooved bars designed to receive and engage the edges of the slides by means of transverse stripsone at either end-pivoted to the grooved bars, and which are likewise pivoted centrally to the frame or plate in which the lens or lenst'ube of the apparatus is iitted in a line drawn diametrically across the opening for the lens or tube, the object of my invention being to provide a slide-holdcr-which is readily adjusted to receive and support slides of difterent widths, and which will properly center the same, irrespective oi' their width, over the center ofthe lens orlens-tube.

ln the accompanying drawing, which is a view in perspective oi' my improved adjustable slide-holder fitted to the lens-plate of a magic-lantern, A represents the plate or board, to which the lens-tube B of the instrument is litted in thc customary manner. B is the opening in the lons-tube over which the transparent picture-slide is to be carried. C C are the longitudinally-grooved parallel bars of the slide-holder. These grooved bars are united by thin transverse plates or strips l) D, oi' equal length, pivoted thereto at each end thereof, so as to allow them to approach and recede from each other, and yet maintain constantly their perfect parallelism. These connectingstrips D D are pivoted centrally at e c' to the face of the board or frame A on each side of the opening B of the lens-tube, and both in a straight line drawn through the center of said tube, so that whatever may be the interval between the grooved bars G C the center of said interval, or of the plate or slide inserted between the bars, shall coincide with the center of the lens. The bars C C are approximated, (see positive lines in the drawing) or are spread apart, (see dotted lines in the drawing,) as required, to receive and secure between them slides or plates S, of any width, by simply swinging the bars upon the pivoted strips, which are readily turned upon their central pivots for the purpose. Wh en the distance between the grooved loa-rs C C of the slide-holder is adjusted to suit the size of the plate at hand, the holder may be fixed by means of a nut, E, led upon a thread cut upon one of the pivot-pins c, said nut being tted with a handle, f, to allow of its being readily lengthened upon the pivot-screw to bind and clamp the pivoted strip and prevent its movement.

I contemplate the substitution of any of the well-known mechanical devices for clamping and locking-the slide-bars instead of the nut E.

I claim as my invention- I The combination, with the lens tube or opening in a magic-lantern, heliostat, or similar instrument, of an adj ustableslide-holder consisting of two movable bars adapted to engage the edges ofthe slide, the opposite edges of which are kept always parallel by means of two parallel transverse strips, each pivoted at its ends to said bars, and in the middle to the plate or frame of 4the instrument on each side of said opening, substantially in the manner and for the purpose herein set forth.

In testimony whereoi` I have signed my name to this specification in the presence of two subscribing witnesses.

XTM. S. BARSTOV.

lVitnesses:

l?. ELBERT Nos'rniixn, A. lV. Srmenr.. 

